In general, a hydraulic hammer, such as a rock drill or an excavator, is essentially used to effectively perform a crushing or excavating work in various civil engineering works.
As shown in FIG. 1, the hydraulic hammer includes a housing 1, a cylinder 2 and a piston 3 provided in the housing 1 to operate using oil pressure or air pressure, and a striking part 4 provided at the front of the cylinder 2, struck by the piston 3, and having a pointed tip to perform the excavating or crushing work. When the piston 3 coupled to the cylinder strikes the striking part 4 in the excavating work using the oil pressure, noise and vibration extremely seriously occur. Noise of 80 dB or more causes a worker or inhabitants to have extremely severe unpleasant feeling and exerts an advert influence on a worker or inhabitants.
In order to solve the above problem, according to the related art, as shown in FIG. 2, a receiving part 5 is formed with a predetermined diameter and a depth at an end of the piston 3 of the cylinder 2 provided in the housing 1 to operate using the oil pressure or the air pressure, and an impact bar 6 mounted on the striking part 4 is inserted into the receiving part 5 as shown in FIG. 2.
In other words, the impact bar 6 which is a portion of the striking part 4 is inserted into the piston 3.
In this case, the piston 3 is moved forward to strike the impact bar 6 mounted on the striking part 4, and the striking is performed in the receiving part 5, so that the noise may be significantly attenuated.
However, according to the related art, since the impact bar is inserted into the piston as described above, the outer surface of the impact bar mutually makes contact with the inner surface of the piston so that the impact bar and the piston may be cracked.
This is because the striking part may be moved forward and backward in a direction inclined at a predetermined angle instead of a correct linear direction.
Accordingly, as described above, cracks may be made, and heat radiation may be difficult in the configuration of the conventional receiving part, so that durability and strength may be degraded.
Meanwhile, since the hydraulic hammer is a well-known technology, and described in detail in the following prior art, the detailed description and drawings of the hydraulic hammer will be omitted in the specification of the present invention.